Lipoic acid/trometamol assembled hydrogel as injectable bandage for hypoxic wound healing at high altitude

Abstract

To avoid chronic wound formation caused by hypoxia and cold in high-altitude areas, developing an injectable, strongly adhesive hydrogel bandage with controllable oxygen generation and inflammation regulation functions is of great value. Poly(lipoic acid) (PLA)-based adhesives have been well-developed from polymerization of α-Lipoic acid (LA), showing attractive performances including simple preparation, strong adhesion, anti-inflammatory. However, injection of PLA-based adhesives has not been well-practiced because of its high viscosity and strong adhesion. Herein, LA and trometamol are firstly found to rapidly gel into a supramolecular hydrogel within 5 min at room temperature, exhibiting well-performed injectability. Further presence of Ce3+ significantly accelerates this gelation within 2 min. Meanwhile, dopamine (DA) and g-C3N4 nanosheet synergistically endow the injectable hydrogel with photothermal function, which can convert near-infrared-light (NIR) into heat, triggering LA polymerization and achieving post-injection enhancement. In terms of bandage performance after molding, the introduction of Ce3+, DA, and g-C3N4 contributes to the improvement of mechanical and adhesion properties. The injectable hydrogel bandage not only possesses highly tough and adhesive features, but also produces oxygen under NIR irradiation, effectively alleviating wound hypoxia, creating anti-inflammatory microenvironment, and significantly promoting healing of incision in a low-pressure oxygen environment.